Helicopter tank



FIG. 1 is a front elevation of the helicopter tank;

FIG. 2 is a rear elevation thereof;

FIG. 3 is a side elevation thereof looking from the left side of FIG. 2;

FIG. 4 is a side elevation thereof looking from the right side of FIG. 2;

FIG. 5 is a top plain view thereof;

FIG. 6 is a bottom view thereof taken on line 6--6 of FIG. 2. 

The ornamental design for a helicopter tank, as shown. 